If you've played any Call of Duty before (campaign), you already know what these Enemy Intel are. If not then let me explain you. Enemy Intel gives you precisely that, intelligence from the enemy which you can view in the Mission Select menu. Do they have purposes other that? Nope. You get 2 Trophies by collecting them all.
There are 45 Enemy Intel scattered throughout all 15 missions. There are 3 in each and some of them are really hidden so that's where this guide comes in. They appear as neon-purple laptops and are semi translucent so keep your eyes peeled for them.